/*
 * Copyright (C) 2005-2011 MaNGOS <http://www.getmangos.com/>
 *
 * Copyright (C) 2008-2011 Trinity <http://www.trinitycore.org/>
 *
 * Copyright (C) 2010-2011 ProjectSkyfire <http://www.projectskyfire.org/>
 * 
 * Copyright (C) 2011 ArkCORE <http://www.arkania.net/>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "Cryptography/BigNumber.h"
#include <openssl/bn.h>
#include <algorithm>

BigNumber::BigNumber() {
	_bn = BN_new();
	_array = NULL;
}

BigNumber::BigNumber(const BigNumber &bn) {
	_bn = BN_dup(bn._bn);
	_array = NULL;
}

BigNumber::BigNumber(uint32 val) {
	_bn = BN_new();
	BN_set_word(_bn, val);
	_array = NULL;
}

BigNumber::~BigNumber() {
	BN_free(_bn);
	if (_array)
		delete[] _array;
}

void BigNumber::SetDword(uint32 val) {
	BN_set_word(_bn, val);
}

void BigNumber::SetQword(uint64 val) {
	BN_add_word(_bn, (uint32) (val >> 32));
	BN_lshift(_bn, _bn, 32);
	BN_add_word(_bn, (uint32) (val & 0xFFFFFFFF));
}

void BigNumber::SetBinary(const uint8 *bytes, int len) {
	uint8 t[1000];
	for (int i = 0; i < len; i++)
		t[i] = bytes[len - 1 - i];
	BN_bin2bn(t, len, _bn);
}

void BigNumber::SetHexStr(const char *str) {
	BN_hex2bn(&_bn, str);
}

void BigNumber::SetRand(int numbits) {
	BN_rand(_bn, numbits, 0, 1);
}

BigNumber BigNumber::operator=(const BigNumber &bn) {
	BN_copy(_bn, bn._bn);
	return *this;
}

BigNumber BigNumber::operator+=(const BigNumber &bn) {
	BN_add(_bn, _bn, bn._bn);
	return *this;
}

BigNumber BigNumber::operator-=(const BigNumber &bn) {
	BN_sub(_bn, _bn, bn._bn);
	return *this;
}

BigNumber BigNumber::operator*=(const BigNumber &bn) {
	BN_CTX *bnctx;

	bnctx = BN_CTX_new();
	BN_mul(_bn, _bn, bn._bn, bnctx);
	BN_CTX_free(bnctx);

	return *this;
}

BigNumber BigNumber::operator/=(const BigNumber &bn) {
	BN_CTX *bnctx;

	bnctx = BN_CTX_new();
	BN_div(_bn, NULL, _bn, bn._bn, bnctx);
	BN_CTX_free(bnctx);

	return *this;
}

BigNumber BigNumber::operator%=(const BigNumber &bn) {
	BN_CTX *bnctx;

	bnctx = BN_CTX_new();
	BN_mod(_bn, _bn, bn._bn, bnctx);
	BN_CTX_free(bnctx);

	return *this;
}

BigNumber BigNumber::Exp(const BigNumber &bn) {
	BigNumber ret;
	BN_CTX *bnctx;

	bnctx = BN_CTX_new();
	BN_exp(ret._bn, _bn, bn._bn, bnctx);
	BN_CTX_free(bnctx);

	return ret;
}

BigNumber BigNumber::ModExp(const BigNumber &bn1, const BigNumber &bn2) {
	BigNumber ret;
	BN_CTX *bnctx;

	bnctx = BN_CTX_new();
	BN_mod_exp(ret._bn, _bn, bn1._bn, bn2._bn, bnctx);
	BN_CTX_free(bnctx);

	return ret;
}

int BigNumber::GetNumBytes(void) {
	return BN_num_bytes(_bn);
}

uint32 BigNumber::AsDword() {
	return (uint32) BN_get_word(_bn);
}

bool BigNumber::isZero() const {
	return BN_is_zero(_bn) != 0;
}

uint8 *BigNumber::AsByteArray(int minSize, bool reverse) {
	int length = (minSize >= GetNumBytes()) ? minSize : GetNumBytes();

	if (_array) {
		delete[] _array;
		_array = NULL;
	}
	_array = new uint8[length];

	// If we need more bytes than length of BigNumber set the rest to 0
	if (length > GetNumBytes())
		memset((void*) _array, 0, length);

	BN_bn2bin(_bn, (unsigned char *) _array);

	if (reverse)
		std::reverse(_array, _array + length);

	return _array;
}

const char *BigNumber::AsHexStr() {
	return BN_bn2hex(_bn);
}

const char *BigNumber::AsDecStr() {
	return BN_bn2dec(_bn);
}
